undecided

Etymology

From Middle English undecided, equivalent to un- + decided.

adj

1. Open and not yet settled or determined.
   The question of man's destiny is still undecided.
2. Uncommitted, not having reached a decision.
   The result of the election is in doubt because of a large number of undecided voters.

noun

1. A voter etc. who has not yet come to a decision.
   The real drama came as these two camps fought for undecideds, who literally found themselves in the middle. February 17, 2008, Jennifer Finney Boylan, “At the Maine Caucuses, a Tough Nut to Crack”, in New York Times
   […] but that is a highly flawed procedure if the undecideds differ in major ways from the decideds. 2016, Herb Asher, Polling and the Public: What Every Citizen Should Know

verb

1. simple past and past participle of undecide